I don't think there IS an area with no nanites at this point. If there's quadrillions of them, to the point where they're floating in the air being breathed in, they're in everything. After 15 years to spread and presumably replicate, no avoiding them. World-wide, as you'd get them into the water and jetstream, and they'd travel the world in short order.

No "nanite Raid", then?

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